"The word 'subsidy' is misused in many situations," Mansouri was quoted as saying by the Khaleej Times. "Unless there's proof and you put it there, you should not use the word subsidy."

In a 55-page report, the US airlines and labour groups said the three Gulf fliers had benefitted unfairly from huge interest-free loans, subsidised airport charges, government protection on fuel losses and below-market labour costs that are considered unfair subsidies by the World Trade Organization.

Western airlines have long complained about competition from the three Gulf carriers, which have turned their home airports into major hubs on transcontinental routes.